🩹 Fix code smells

Sources/Model/Dice/DieManager.cs

@@ -4,6 +4,6 @@ namespace Model.Dice
 {
     public class DieManager
     {
-        private IEnumerable<Die> dice = new List<Die>();
+        private readonly IEnumerable<Die> dice = new List<Die>();
     }
 }

Sources/Model/Dice/FavGroupManager.cs

@@ -6,7 +6,7 @@ namespace Model.Dice
     {
         private IEnumerable<FavGroup> favGroups;
 
-        private DieManager dieManager;
+        private readonly DieManager dieManager;
 
         public FavGroupManager(DieManager dieManager)
         {

Sources/Model/Games/Game.cs

@@ -10,7 +10,7 @@ namespace Model.Games
     {
         public string Name { get; private set; }
 
-        private IEnumerable<Turn> turns = new List<Turn>();
+        private readonly IEnumerable<Turn> turns = new List<Turn>();
 
         public Game(string name)
         {

Sources/Model/Games/GameRunner.cs

@@ -10,9 +10,9 @@ namespace Model.Games
 {
     public class GameRunner
     {
-        private PlayerManager globalPlayerManager;
+        private readonly PlayerManager globalPlayerManager;
-        private FavGroupManager favGroupManager;
+        private readonly FavGroupManager favGroupManager;
-        private IEnumerable<Game> games;
+        private readonly IEnumerable<Game> games;
 
         public GameRunner(PlayerManager globalPlayerManager, FavGroupManager favGroupManager, IEnumerable<Game> games)
         {

Sources/Model/Games/Turn.cs

@@ -29,13 +29,17 @@ namespace Model.Games
         /// </summary>
         public readonly Player player;
 
-        private IEnumerable<AbstractDieFace> faces;
+        /// <summary>
+        /// the collection of Face that were rolled
+        /// </summary>
+        private readonly IEnumerable<AbstractDieFace> faces;
 
         /// <summary>
         /// this private constructor is to be used only by factories
         /// </summary>
         /// <param name="when">date and time of the turn</param>
         /// <param name="player">player who played the turn</param>
+        /// <param name="faces">faces that were rolled</param>
         private Turn(DateTime when, Player player, IEnumerable<AbstractDieFace> faces)
         {
             this.when = when;
@@ -51,6 +55,7 @@ namespace Model.Games
         /// </summary>
         /// <param name="when">date and time of the turn</param>
         /// <param name="player">player who played the turn</param>
+        /// <param name="faces">faces that were rolled</param>
         /// <returns>a new Turn object</returns>
         public static Turn CreateWithSpecifiedTime(DateTime when, Player player, IEnumerable<AbstractDieFace> faces)
         {
@@ -75,6 +80,7 @@ namespace Model.Games
         /// creates a Turn with a default time, which is "now" in UTC. 
         /// </summary>
         /// <param name="player">player who played the turn</param>
+        /// <param name="faces">faces that were rolled</param>
         /// <returns>a new Turn object</returns>
         public static Turn CreateWithDefaultTime(Player player, IEnumerable<AbstractDieFace> faces)
         {